It is possible to do it but not at the small size due to the tiny face issue. I did it using “The Dave Method” without any trouble. I used Follow Me to radius the outside and the top end. For the inner radius I use Ctrl+Push/Pull and ran the radius a little way off the end. Then an Intersect Faces and erase the waste.
RailsAndStilesOuterProfile dr.skp (79.1 KB)